作者:Jiyoon Heo、Chozhidakath Damodharan Sunesh、Suin Jo、Youngson Choe
DOI:10.1166/jnn.2017.14137
日期:2017.8.1
Herein, we report two new cationic iridium(III) complexes using oxazoline based ancillary ligand, namely, [Ir(ppy)2(mdpox)]PF6 (Complex 1) and [Ir(dfppy)2(mdpox)]PF6 (Complex 2), where ppy is 1-phenyl pyridine, dfppy is 2-(2,4-difluorophenyl)pyridine, and mdpox is 2,2-methylenebis(4,5- diphenyl-2-oxazoline). The solution photoluminescence (PL) emission spectra shows structured emission bands for both complexes which emit blue-green and blue phosphorescence for Complex 1 and 2, respectively. To gain an insight into the photophysical and electrochemical features of the iridium complexes, DFT calculations were performed, which shows the highest occupied molecular orbital (HOMO) is located on d orbitals of iridium center and π orbitals of the phenyl group of cyclometalated ligands, whereas the lowest unoccupied molecular orbital (LUMO) is distributed on iridium atom and one of the cyclometalated ligand. Light-emitting electrochemical cells (LECs) were fabricated employing these complexes and investigated their electroluminescent properties. LECs based on these complexes resulted yellow and green electrolunescence for Complex 1 and 2, respectively. A high luminance of 838 cd m-2 and a current density of 486 mA cm-1 has achieved for Complex 1 owing to the more balanced charge carrier injection and recombination.
在此,我们报告了两种使用噁唑啉辅助配体的新型阳离子铱(III)配合物,即[Ir(ppy)2(mdpox)]PF6(配合物 1)和[Ir(dfppy)2(mdpox)]PF6(配合物 2)、其中 ppy 为 1-苯基吡啶,dfppy 为 2-(2,4-二氟苯基)吡啶,mdpox 为 2,2-亚甲基双(4,5-二苯基-2-噁唑啉)。溶液光致发光(PL)发射光谱显示,这两种复合物的发射波段结构合理,复合物 1 和复合物 2 分别发出蓝绿色和蓝色磷光。为了深入了解铱配合物的光物理和电化学特征,研究人员进行了 DFT 计算,结果表明最高占有分子轨道(HOMO)位于铱中心的 d 轨道和环甲基化配体苯基的 π 轨道上,而最低未占有分子轨道(LUMO)分布在铱原子和环甲基化配体之一上。利用这些配合物制作了发光电化学电池(LEC),并研究了它们的电致发光特性。基于这些复合物的发光电化学电池在复合物 1 和 2 中分别产生了黄色和绿色电致发光。由于电荷载流子注入和重组更为平衡,复合物 1 的亮度高达 838 cd m-2,电流密度为 486 mA cm-1。